As time goes by I don't see much of a difference. If I spent six months building something for client A and then a year doing something entirely different for client B, I will have to puzzle out what my intentions were a year ago just as I would have to do maintaining code anybody else wrote. Truly agile developers approach development by building a working system that can run but is far from the requirements and the…
80% Maintaining.
There was an article on HN. A while back about the value of maintainers over innovators. Keeping stuff ticking along is just as important and under valued (was the gist).